Mechanosensing of substrate stiffness regulates focal adhesions dynamics in cell

Cell mechanical recognition of extracellular matrix determines the cell activities and functions. Focal adhesions are part of the cell mechanosensing machinery and, operating at the very dynamic interface between cell and extracellular matrix, can operate this recognition and trigger conformational, functional and behavioral modification of the cell. To investigate how the dynamic of assembly and disassembly of focal adhesion are influenced by the substrate mechanics we developed a novel procedure. The analysis consists of the over time tracking of focal adhesion structures in a stable cell line of NIH/3T3 expressing fluorescent pmKate2-paxillin. From collected signals and by their autocorrelation we evaluated the average lifetime and assembly rate of focal adhesion as function of substrate stiffness. Further, by signals cross-correlation we obtained information about the mechanical nature of cytoskeleton and its network. This quantitative approach to focal adhesion dynamics characterization was presented in this study as an investigation tool for cell mechanobiology.